1. Field of the Invention
The present invention relates to a passive radio-frequency identification (RFID) system using a high-frequency (HF) band, particularly 13.56 megahertz (MHz), and more particularly, to a system and an apparatus for simultaneously identifying stacked RFID tags and massive RFID tags using an HF band.
2. Description of the Related Art
A passive radio-frequency identification (RFID) system using a high frequency band, particularly 13.56 MHz, includes a tag having object information and a reader.
The tag of the passive RFID system using the HF band receives a carrier wave from the reader via magnetic coupling in a radio environment.
The tag is powered through the received carrier wave and communicates with the reader via load modulation.
Applications of RFID continue to expand from pellet or box level identification to individual item level identification. Recently, ISO/IEC 18000-3 Mode 3 (hereinafter, defined as an HF Gen2 international standard), in which an ultrahigh frequency (UHF) high-performance Gen2 protocol standard is applied to an HF band suitable for metal and liquids, has established.
A conventional amplitude-shift keying (ASK) HF international standard mainly performs one-to-one reader-tag communications. Thus, application of a conventional RFID system is limited to, for example, identification of a small number of tags.
In addition, the conventional technology involves a slow identification speed and limitations in tag identification performance due to an envelope detection method. Thus, in order to overcome theses technical problems, the present invention discloses an HF RFID apparatus and method for simultaneously identifying a plurality of stacked tags at a high speed in accordance with the recent HF Gen2 international standard.